Wireless power feeding unit, power transmitting module, power receiving module, and wireless power transmission system

Abstract

A wireless power feeding unit includes a power transmitting module and a power receiving module. The power transmitting module includes: a first inverter circuit which is connected to a power source via a switch; a first transmission coil connected to the first inverter circuit; a second inverter circuit which is connected to the power source or another power source not via the switch; a second transmission coil which is connected to the second inverter circuit; and a power transmission control circuit which controls the first and second inverter circuits. The power receiving module includes a first reception coil opposed to the first transmission coil and a second reception coil opposed to the second transmission coil. During operation of the first and second inverter circuits, even while supply of power to the first inverter circuit is stopped, the power transmission control circuit maintains control of the second inverter circuit.

What is claimed is: 
     
       1. A wireless power feeding unit comprising:
 a power transmitting module; and 
 a power receiving module, 
 the power transmitting module including
 a first transmission coil which is connected to a first inverter circuit configured to convert supplied electric power into first AC power and output the first AC power, and which is configured to send out the first AC power, 
 a second transmission coil which is connected to a second inverter circuit configured to convert supplied electric power into second AC power and output the second AC power, and which is configured to send out the second AC power, 
 
 and 
 the power receiving module including
 a first reception coil which is opposed to the first transmission coil, and which receives at least a portion of the first AC power, and 
 a second reception coil which is opposed to the second transmission coil, and which receives at least a portion of the second AC power, wherein, 
 
 at least a portion of the AC power received by the first reception coil is supplied to a first load; 
 at least a portion of the AC power received by the second reception coil is supplied to a second load; 
 one of the first and second transmission coils is inside another of the first and second transmission coils; 
 one of the first and second reception coils is inside another of the first and second reception coils; 
 each of the two coils in at least one of the power transmission power module and the power receiving module is covered by a piece of magnetic substance, an interspace existing between the pieces of magnetic substance covering the two coils. 
 
     
     
       2. The wireless power feeding unit of  claim 1 , wherein each of the two coils has an annular shape and the two coils are disposed coaxially. 
     
     
       3. The wireless power feeding unit of  claim 1 , wherein at least one of the power transmitting module and the power receiving module further includes an electrically conductive shield inside the interspace. 
     
     
       4. The wireless power feeding unit of  claim 3 , wherein the shield has an annular shape. 
     
     
       5. The wireless power feeding unit of  claim 3 , wherein the shield has a slit. 
     
     
       6. The wireless power feeding unit of  claim 3 , wherein the shield includes electrically conductive paint coating a side wall of at least one of the pieces of the magnetic substance, the side wall facing the interspace. 
     
     
       7. The wireless power feeding unit of  claim 3 , wherein the shield includes an electrically conductive tape attached on a side wall of at least one of the pieces of the magnetic substance, the side wall facing the interspace. 
     
     
       8. The wireless power feeding unit of  claim 1 , wherein the interspace is an air gap. 
     
     
       9. The wireless power feeding unit of  claim 1 , wherein:
 each of the first transmission coil, the second transmission coil, the first reception coil, and the second reception coil is covered by a piece of magnetic substance; 
 a first interspace exists between the pieces of magnetic substance covering the first and second transmission coils; and 
 a second interspace exists between the pieces of magnetic substance covering the first and second reception coils. 
 
     
     
       10. The wireless power feeding unit of  claim 9 , wherein:
 the power transmitting module further includes an electrically conductive first shield inside the first interspace; and 
 the power receiving module further includes an electrically conductive second shield inside the second interspace. 
 
     
     
       11. The wireless power feeding unit of  claim 1 , wherein the power transmitting module further includes:
 the first inverter circuit; 
 the second inverter circuit; and 
 a power transmission control circuit configured to control the first and second inverter circuits. 
 
     
     
       12. The wireless power feeding unit of  claim 11 , wherein:
 the first inverter circuit is connected to a power source via a switch; 
 the second inverter circuit is connected to the power source or another power source not via the switch; and 
 the power transmission control circuit is connected to the power source or another power source not via the switch, and is configured, during operation of the first and second inverter circuits, to maintain control of the second inverter circuit, even if the switch is turned OFF to stop supply of power to the first inverter circuit. 
 
     
     
       13. A wireless power transmission system comprising:
 the wireless power feeding unit of  claim 1 ; and 
 an apparatus including the first load and the second load control circuit. 
 
     
     
       14. The power transmitting module in the wireless power feeding unit of  claim 1 , wherein each of the first and second transmission coils is covered by a piece of magnetic substance, an interspace existing between the pieces of magnetic substance covering the first and second transmission coils. 
     
     
       15. The power receiving module in the wireless power feeding unit of  claim 1 , wherein each of the first and second reception coils is covered by a piece of magnetic substance, an interspace existing between the pieces of magnetic substance covering the first and reception coils.